Portion of a display screen with a transitional user interface



FIG. 1 is a first state of the transitional user interface for a portion of a display screen of my new design;

FIG. 2 is a second state thereof;

FIG. 3 is a third state thereof;

FIG. 4 is a fourth state thereof;

FIG. 5 is a fifth state thereof;

FIG. 6 is a sixth state thereof; and,

FIG. 7 is a seventh state thereof.

The appearance of the transitional user interface sequentially transitions between the images shown in FIGS. 1-7. The process or period in which one image transitions to another image forms no part of the claimed design.

The boundaries of the transitional user interface and the portion of the display screen upon which the design appears are congruent. 

The ornamental design for a portion of a display screen with a transitional user interface, as shown and described. 